[virt-tools-list] [PATCH virt-viewer v2] Fix a regression when initial connection fails

[Christophe Fergeau]

Acked-by: Christophe Fergeau <cfergeau at redhat.com>

On Thu, Jan 31, 2019 at 09:04:11AM -0600, Jonathon Jongsma wrote:
> Due to changes in commit 65ef66e4, when the initial connection fails,
> virt-viewer just sat quietly and didn't indicate what was wrong. It also
> did not exit as it did before.  This is because we were using
> virt_viewer_session_spice_channel_destroy() incorrectly. This function
> was intended to be a callback that is called to clean up the VV session
> when the SpiceSession tells us that a channel has been destroyed. It
> does not actually destroy the channel, it only cleans up references to
> that channel within virt-viewer. After calling this function, the
> channel is not affected in any way. If the channel object was valid
> before calling the function, it will be valid and unchanged after
> calling the function as well.
> 
> The problem is that before commit 65ef66e4, this function
> (_channel_destroy()) also had a side-effect of emitting a signal that
> made us think that the SpiceSession was disconnected when it was not.
> The application responded to this signal by exiting even though the
> session was not properly disconnected and cleaned up.
> 
> We now no longer exit the application until the SpiceSession is properly
> disconnected and cleaned up. So we need to make sure that this happens
> when our initial connection fails. Therefore, when the main channel
> receives an error channel-event, we should not call
> virt_viewer_session_spice_channel_destroy(). This function should only
> be called when a channel has actually been destroyed, and the channel is
> not destroyed at this point.  We should instead explicitly disconnect
> the session, which will result in the channels being destroyed properly.
> After the session destroys all of the channels, the 'channel-destroy' signal
> will be emitted by SpiceSession, so the _channel_destroy() function will
> eventually get called by the signal handler.
> 
> To make the proper use of the function more obvious, I also changed the
> function name from _channel_destroy() to _channel_destroyed() and added
> a comment.
> 
> Fixes: rhbz#1666869
> Signed-off-by: Jonathon Jongsma <jjongsma at redhat.com>
> ---
> 
> Changes in v2:
>  - change function name to _channel_destroyed()
> 
>  src/virt-viewer-session-spice.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/src/virt-viewer-session-spice.c b/src/virt-viewer-session-spice.c
> index f76c7f9..5e214cd 100644
> --- a/src/virt-viewer-session-spice.c
> +++ b/src/virt-viewer-session-spice.c
> @@ -72,9 +72,9 @@ static void virt_viewer_session_spice_usb_device_selection(VirtViewerSession *se
>  static void virt_viewer_session_spice_channel_new(SpiceSession *s,
>                                                    SpiceChannel *channel,
>                                                    VirtViewerSession *session);
> -static void virt_viewer_session_spice_channel_destroy(SpiceSession *s,
> -                                                      SpiceChannel *channel,
> -                                                      VirtViewerSession *session);
> +static void virt_viewer_session_spice_channel_destroyed(SpiceSession *s,
> +                                                        SpiceChannel *channel,
> +                                                        VirtViewerSession *session);
>  static void virt_viewer_session_spice_session_disconnected(SpiceSession *s,
>                                                             VirtViewerSessionSpice *session);
>  static void virt_viewer_session_spice_smartcard_insert(VirtViewerSession *session);
> @@ -400,7 +400,7 @@ create_spice_session(VirtViewerSessionSpice *self)
>      virt_viewer_signal_connect_object(self->priv->session, "channel-new",
>                                        G_CALLBACK(virt_viewer_session_spice_channel_new), self, 0);
>      virt_viewer_signal_connect_object(self->priv->session, "channel-destroy",
> -                                      G_CALLBACK(virt_viewer_session_spice_channel_destroy), self, 0);
> +                                      G_CALLBACK(virt_viewer_session_spice_channel_destroyed), self, 0);
>      virt_viewer_signal_connect_object(self->priv->session, "disconnected",
>                                        G_CALLBACK(virt_viewer_session_spice_session_disconnected), self, 0);
>  
> @@ -776,14 +776,14 @@ virt_viewer_session_spice_main_channel_event(SpiceChannel *channel,
>                  spice_session_connect(self->priv->session);
>              }
>          } else {
> -            virt_viewer_session_spice_channel_destroy(NULL, channel, session);
> +            spice_session_disconnect(self->priv->session);
>          }
>          break;
>      }
>      case SPICE_CHANNEL_ERROR_IO:
>      case SPICE_CHANNEL_ERROR_LINK:
>      case SPICE_CHANNEL_ERROR_TLS:
> -        virt_viewer_session_spice_channel_destroy(NULL, channel, session);
> +        spice_session_disconnect(self->priv->session);
>          break;
>      default:
>          g_warning("unhandled spice main channel event: %d", event);
> @@ -1111,10 +1111,11 @@ virt_viewer_session_spice_session_disconnected(G_GNUC_UNUSED SpiceSession *s,
>      g_signal_emit_by_name(self, "session-disconnected", error ? error->message : NULL);
>  }
>  
> +/* called when the spice session indicates that a session has been destroyed */
>  static void
> -virt_viewer_session_spice_channel_destroy(G_GNUC_UNUSED SpiceSession *s,
> -                                          SpiceChannel *channel,
> -                                          VirtViewerSession *session)
> +virt_viewer_session_spice_channel_destroyed(G_GNUC_UNUSED SpiceSession *s,
> +                                            SpiceChannel *channel,
> +                                            VirtViewerSession *session)
>  {
>      VirtViewerSessionSpice *self = VIRT_VIEWER_SESSION_SPICE(session);
>      int id;
> -- 
> 2.17.2
> 
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